Kinetics, isotherms, effect of structure, and computational analysis during the removal of three representative pharmaceuticals from water by adsorption using a biochar obtained from oil palm fiber

Acetaminophen (ACE), cephalexin (CPX), and valsartan (VAL) are recognized water pollutants, which can be removed by adsorption. Herein, the removal of these pharmaceuticals using a biochar (BP), prepared from oil palm fiber, was tested. It was studied the structural effects of the pharmaceuticals and biochar on the adsorption process supported by experimental and computational results, plus characterizations of the material. The biochar has 76.05 m(2) g(-1) of surficial area, and carboxylic groups (1.343 mmol g(-1)) predominantly. The maximum adsorption uptakes were 7.3, 7.9, and 23.85 mg g(-1) for ACE, CPX, and VAL, respectively; following pseudo-second-order kinetics. The best pollutants removal was obtained at acidic pH (3.0). Computational analyses indicated that oxygenated groups of BP (able to generate H-bond interactions) influenced the adsorption of pharmaceuticals. It can be remarked that BP is a low-cost adsorbent synthesized easily from wastes, with high feasibility to remove pharmaceutical structures from water.

Automated summary

The biochar prepared from oil palm fiber showed high efficiency in removing acetaminophen, cephalexin, and valsartan from water, with maximum adsorption uptakes observed under acidic pH conditions. Computational analyses indicated that oxygenated groups of biochar influenced the adsorption of pharmaceuticals through H-bond interactions, highlighting the potential of biochar as a low-cost and effective adsorbent for pharmaceutical removal from water.